Colonoscopies: More is not always better, new studies say

March 11, 2013
| by Hiu Chung So

Colonoscopy is often considered to be the gold standard of colorectal cancer screening methods, because it can survey the entire length of the colon and can remove precancerous polyps and biopsy suspicious tissue during the procedure.

Colonoscopy may be the gold standard of colorectal cancer detection, but once a decade is enough for most Americans, experts say.

However, the procedure comes with its own risks and complications, and two March 11 JAMA Internal Medicine studies remind patients and physicians to stick to screening guidelines established by the U.S. Preventive Services Task Force (USPSTF) and American College of Physicians (ACP), and that performing them more often than recommended may do more harm than good.

The first study, titled “Potentially Inappropriate Screening Colonoscopy in Medicare Patients,” examined all colonoscopy Medicare claims filed in Texas and a sample of claims from the U.S. in 2008-2009. After evaluating the claims, the authors found that over 23 percent of colonoscopies performed on patients age 70 or older are “potentially inappropriate” by USPSTF standards, meaning the procedure is either done more frequently than recommended, or being done when there is no indication for it.

Marwan Fakih, M.D., co-director of City of Hope’s Gastrointestinal Cancer Program, said that this study “suggests a lack of general adherence to the USPSTF and ACP recommendations, with two negative consequences: increased patient risk and higher societal health care cost.”

But the actual number of inappropriate colonoscopies is likely lower than the paper suggests.

Because the authors relied on Medicare claims data, there may have been undocumented information — such as patients' symptoms or changes in bowel movement habits — that may have suggested a colonoscopy, Fakih said.

The second JAMA Internal Medicine paper, “Complications Following Colonoscopy With Anesthesia Assistance,” examined U.S. Medicare data and found that colonoscopies carry a low — less than 0.2 percent — but significant risk of complications, including bowel perforations, splenic injury and aspiration pneumonia (inflamed lungs from inhaling foreign material). Upon further analysis, the authors found that those who received anesthesia were more likely to have complications, particularly aspiration pneumonia.

“These risks have been previously described and are well-known complications of colonoscopy, [but] this study is the first to quantify them in Medicare patients,” said Fakih, who is not involved in either study.

In light of these findings, Fakih said further efforts should be made to identify, refine and model colonoscopy's risk-benefits for populations of varying ages and risks for colorectal cancer. But in the meantime, he concurs with the USPSTF recommendations, which include routine colorectal cancer screenings for Americans ages 50 to 75 (starting younger for those with a family history of colorectal cancer), screenings when indicated for those 75 to 85, and against screenings for those older than 85.